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Topic: Due won't start after power off-on, have to reset (Read 57775 times) previous topic - next topic

Nottelmann

Fitting R99 on my so-called compatible Due board solved all reset problems and it is now working exactly as the genuine Due board I also have.

Thanks to dancombine for your support!

earx

dancombine: this seems to work nicely. i previously tried the 10u cap + 470R solution, but that did not work on all due's it seemed..

however, the 0603 soldering is a nightmare for me, especially on a fully populated board with headers sticking out and all. wow! is there a special soldering iron tip you can recommend? i'm afraid i might mess up a board or two if do this with my current soldering technique..


Moderator edit: Language.

ZartPARZ

According to dancombine's suggestion, I put normal through-hole 10k resistor in. Everything work correctly. The DUE start the sketch every time I put power in. Thank to dancombine. ;)

Alexwalex

Thank you, dancombine!! I put 10k resistor (R99 in schematics) and DUE now starts correctly.

RayLivingston

Hi all,

I have the same problem since the beginning, and this is bugging me big time for my projects. I think I have identified a definite solution.
In fact credit is due to the guys of Freetronics about the EtherDue.
see link http://forum.freetronics.com/viewtopic.php?f=45&t=6055

The DUE boards may be affected by the following bug: On power-on the board may start to the bootloader instead of running the onboard program, as if the ERASE button had been pressed. Pressing "reset" resumes normal operation. The bug appears to be caused by undocumented behaviour in the ATSAM3X8E microcontroller regarding the "erase" input pin - according to the specification we shouldn't ever be seeing this.

The fix is to solder a surface mount resistor (0603 size) onto the board: solder a 10k resistor between the ERASE line and +3.3V, close to fet T3. In practice, solder it across the 2 upper pins of T3.

To know if you have a DUE (or derivate/clone) that may be affected, check if fet T3 is soldered horizontally - see picture below:
(fet T3 is in the middle of the picture, just to the right of the 6-pin SPI connector)



(If your DUE has the fet soldered vertically, likely the board is more recent and good, as it has resistor R99 soldered.)


Here is a picture of a fixed DUE with a 10k resistor that I soldered across the pins of T3:




I have tested this and works fine.

-D






I am still battling this problem on most of my Due boards, but this fix confuses me....  Per the datasheet, ERASE needs to be pulled low to disable ERASE mode.  The above text says:

Quote
The fix is to solder a surface mount resistor (0603 size) onto the board: solder a 10k resistor between the ERASE line and +3.3V
This suggests the 10K resistor is being added as a PULLUP to the ERASE pin.  Or is it actually being added between ERASE_CMD signal and GND?  Though the schematic indicates there should already be a resistor in that position.  What am I missing?

Also, if I never need the ERASE function, could I not simply remove the ERASE switch and MOSFET entirely, and hard-wire the ERASE pin to GND?

Regards,
Ray L.

westfw

Quote
if I never need the ERASE function
What I've read suggests that Due ALWAYS needs the erase function, even if you don't use the switch.
http://www.arduino.cc/en/Guide/ArduinoDue


RayLivingston

Well, it does appear adding the 10K resistor has "fixed" one of my boards!  I'll have to try a few more.

Regards,
Ray L.

westfw

Quote
This suggests the 10K resistor is being added as a PULLUP to the ERASE pin.  Or is it actually being added between ERASE_CMD signal and GND?
The freetronics page says that the resistor was added in a later version of the Arduino reference schematic, and I can confirm that it is present in V03 of the schematics, and NOT in V02

The resistor is a pullup on the RESET_CMD signal, which goes to the gate of a P-channel MOSFET before doing anything to the SAM3X.  ERASE_CMD is the signal from the 16u2, thus, it serves to hold the transistor "OFF" when the erase signal from the 16u2 is floating.   It is NOT between +3.3V and the actual RESET signal!

I'm not sure how this qualifies as "undocumented behavior of the chip."  Seems like a simple bug (probably in the 16u2) to me.  It'd be nice if the sites advertising fixes went into more technical detail (including a schematic/circuit description of the fix, and not just physical photographs!)


sined23

#53
Apr 09, 2016, 07:02 pm Last Edit: Apr 11, 2016, 07:49 am by sined23
I upgraded 16u2 to fix it.
Firmware is here https://forum.arduino.cc/index.php?action=dlattach;topic=167492.0;attach=52901

Description of change you can find in that topic.

RayLivingston

#54
Apr 10, 2016, 03:25 am Last Edit: Apr 10, 2016, 03:26 am by RayLivingston
I upgraded 16u2 to fix it.
Firmware is here https://forum.arduino.cc/index.php?action=dlattach;topic=167492.0;attach=52901

Description of change you can fin in that topic.
That link downloads a HEX file  It doesn't point an any "topic"...

So you're saying re-FLASHING the 16U2 fixes this problem?

Regards,
Ray L.

westfw


sined23

#56
Apr 10, 2016, 05:41 pm Last Edit: Apr 10, 2016, 07:04 pm by sined23
So you're saying re-FLASHING the 16U2 fixes this problem?
Yes. The author said that RESET will be LOW for some usec after power on.
However in some msec I see one more RESET :)
But it doesn't metter. More RESETs - better for SAM3X )))


RayLivingston

Yes. The author said that RESET will be LOW for some usec after power on.
However in some msec I see one more RESET :)
But it doesn't metter. More RESETs - better for SAM3X )))


OK.  Sooooo.....  How does one re-FLASH the 16U2?

Regards,
Ray L.

westfw

#58
Apr 11, 2016, 04:34 am Last Edit: Apr 11, 2016, 08:08 am by westfw
Quote
The author said that RESET will be LOW for some usec after power on.
I'll have to admit to being skeptical that the patch changing the power-on reset behavior will have any effect on the "doesn't start sketch after upload" problem that occurs long after power-on...
The thread surrounding the 16u2 patch describes a somewhat different problem than this one.

(Oh; that IS the subject of this thread, isn't it.   My Due Clone won't start the sketch after upload, either.)

sined23

How does one re-FLASH the 16U2?
http://www.arduino.cc/en/Hacking/Upgrading16U2Due

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